Impact of membrane scratches on fuel cell durability

Cost-effective, scalable fuel cell production requires a comprehensive understanding of the potential impacts of various non-uniformities that may be present in the membrane electrode assembly. The present work investigates the fuel cell durability impacts of membrane scratches, which may occur during fabrication. X-ray computed tomography is utilized to track localized degradation phenomena in two purposefully designed fuel cells with scratch-containing reinforced membranes subjected to chemo-mechanical accelerated stress testing. Several effective parameters that control the extent of local degradation in scratch regions are identified as: (i) friction between the catalyst coated membrane and gas diffusion layer (GDL); (ii) scratch width; (iii) obstacles for free membrane deformation; (iv) GDL collapse into the scratched area; and (v) scratch direction. Importantly, two major self-mitigating mechanisms that can support the scratched region chemically and mechanically are identified, namely up to 85 % less chemical degradation in catalyst-free scratched regions and elimination of harmful tensile stress due to membrane-microporous layer fusion under the same conditions. The obtained results indicate that scratches on the membrane can potentially be manageable by controlling the effective parameters. • The impact of membrane scratches on fuel cell durability is investigated. • Scratched membranes are stress tested and visualized in situ using X-ray imaging. • Key influential factors include friction, scratch width, obstacles, and GDL contact. • Two self-stabilizing mechanisms that enhance durability are identified. • Catalyst-free scratched regions experienced up to 85 % less chemical thinning.